Acquiring Timing Advance (ta) Information for a Candidate Cell Using Sounding Reference Signals (srs)

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to acquiring timing advance (TA) information. Some features may enable and provide improved communications, including acquiring TA information for a candidate cell using sounding reference signal (SRS) in L1 and L2 mobility.

Wireless communication networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast, and the like. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. Such networks may be multiple access networks that support communications for multiple users by sharing the available network resources.

A wireless communication network may include several components. These components may include wireless communication devices, such as base stations (or node Bs) that may support communication for a number of user equipments (UEs). A UE may communicate with a base station via downlink and uplink. The downlink (or forward link) refers to the communication link from the base station to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the base station.

A base station may transmit data and control information on a downlink to a UE or may receive data and control information on an uplink from the UE. On the downlink, a transmission from the base station may encounter interference due to transmissions from neighbor base stations or from other wireless radio frequency (RF) transmitters. On the uplink, a transmission from the UE may encounter interference from uplink transmissions of other UEs communicating with the neighbor base stations or from other wireless RF transmitters. This interference may degrade performance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, the possibilities of interference and congested networks grows with more UEs accessing the long-range wireless communication networks and more short-range wireless systems being deployed in communities. Research and development continue to advance wireless technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.

The following summarizes some aspects of the present disclosure to provide a basic understanding of the discussed technology. This summary is not an extensive overview of all contemplated features of the disclosure and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in summary form as a prelude to the more detailed description that is presented later.

In some aspects, the techniques described herein relate to a method of wireless communication performed by a user equipment (UE), the method including receiving an indication of a candidate cell, wherein the UE is transitioning from communicating with an active cell to the candidate cell; determining, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the candidate cell; and transmitting, to the candidate cell, an SRS that includes the TA information.

In some aspects, the techniques described herein relate to a method of wireless communication performed by a first base station, the method including receiving an indication of a UE, wherein the UE is transitioning from communicating with a second base station to the first base station; determining, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the UE; and transmitting, to the UE, an SRS that includes the TA information.

In some aspects, the techniques described herein relate to a user equipment (UE) that includes a memory storing processor-readable code and at least one processor coupled to the memory. The at least one processor may be configured to execute the processor-readable code to cause the at least one processor to: receive an indication of a candidate cell, wherein the UE is transitioning from communicating with an active cell to the candidate cell; determine, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the candidate cell; and transmit, to the candidate cell, an SRS that includes the TA information.

In some aspects, the techniques described herein relate to a first base station that includes a memory storing processor-readable code and at least one processor coupled to the memory. The at least one processor may be configured to execute the processor-readable code to cause the at least one processor to: receive an indication of a UE, wherein the UE is transitioning from communicating with a second base station to the first base station; determine, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the UE; and transmit, to the UE, an SRS that includes the TA information.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.

While aspects and implementations are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, aspects and/or uses may come about via integrated chip implementations and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, artificial intelligence (AI)-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range in spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described aspects. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, radio frequency (RF)-chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders/summers, etc.). It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

The detailed description set forth below, in connection with the appended drawings, is intended as a description of various configurations and is not intended to limit the scope of the disclosure. Rather, the detailed description includes specific details for the purpose of providing a thorough understanding of the inventive subject matter. It will be apparent to those skilled in the art that these specific details are not required in every case and that, in some instances, well-known structures and components are shown in block diagram form for clarity of presentation.

The present disclosure provides systems, apparatus, methods, and computer-readable media that support acquiring TA information using SRSs, which may be received from one or more cells in L1/L2 mobility scenario. In particular, a UE may transition between one or more cells, such as one or more primary cells (PCells), secondary cells (SCells), Primary and Secondary Cells (PSCells), special cells (SpCells), or combinations thereof. When switching in this context, it may be necessary to exchange updated information for the new cell. In particular, it may be necessary to determine TA information, transmit power information, beam management information, and combinations thereof. Mechanisms for determining this information may need to be compatible with L1/L2 signal used to update the cells for a UE, along with other interface signaling. For example, R18 systems for L1/L2 signaling may specify mechanism and procedures of L1/L2 based inter-cell mobility for mobility latency reduction. Such systems may be used to configure and maintain multiple candidate cells to allow fast application of configurations for candidate cells and may include a dynamic switch mechanism among candidate serving cells (including SpCells and SCells) based on L1/L2 signaling. L1 enhancements for inter-cell beam management may include L1 measurement and reporting and beam indication, TA management, and interface signaling (such as Central Unit (CU)-distributed unit (DU) signaling) to support L1/L2 mobility, if needed. Accordingly, L1/L2 based inter-cell mobility may be applicable to the following scenarios (i) standalone, carrier aggregation (CA), and New Radio-Dual Connectivity (NR-DC) cases with serving cell change within one cell group (CG), (ii) Intra-DU cases and intra-CU/inter-DU cases, (iii) intra-frequency and inter-frequency cases in which source/active cells and target cells are synchronized or non-synchronized.

One solution to this problem may be to acquire initial TA information for communication with a new candidate cell based on an SRS set, which may be stored on a current active cell and/or may be stored on a UE. In such implementations, an SRS including the TA information may then be transmitted to the candidate cell, and the TA information may be used in future communication with the candidate cell. In certain implementations, the initial TA information may be further refined based on one or more signal measurements for communications received from a candidate cell (such as based on comparisons to one or more communications received from the active cell). For example, differences in timing, transmit power, and the like may be used to further determine TA information or other SRS information (such as initial transmit power or transmit beam). This may further improve the efficiencies of initially establishing communication with a new candidate cell.

Particular implementations of the subject matter described in this disclosure may be implemented to realize one or more of the following potential advantages or benefits. In some aspects, the present disclosure provides techniques for acquiring uplink timing information, such as TA information, by SRS transmission in ways that reduce the communicative overhead, complexity, and uplink resources. This information may be further refined to additionally improve the quality and efficiency of communication with candidate cells.

th This disclosure relates generally to providing or participating in authorized shared access between two or more wireless devices in one or more wireless communications systems, also referred to as wireless communications networks. In various implementations, the techniques and apparatus may be used for wireless communication networks such as code division multiple access (CDMA) networks, time division multiple access (TDMA) networks, frequency division multiple access (FDMA) networks, orthogonal FDMA (OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks, GSM networks, 5Generation (5G) or new radio (NR) networks (sometimes referred to as “5G NR” networks, systems, or devices), as well as other communications networks. As described herein, the terms “networks” and “systems” may be used interchangeably.

A CDMA network, for example, may implement a radio technology such as universal terrestrial radio access (UTRA), cdma2000, and the like. UTRA includes wideband-CDMA (W-CDMA) and low chip rate (LCR). CDMA2000 covers IS-2000, IS-95, and IS-856 standards.

A TDMA network may, for example implement a radio technology such as Global System for Mobile Communication (GSM). The 3rd Generation Partnership Project (3GPP) defines standards for the GSM EDGE (enhanced data rates for GSM evolution) radio access network (RAN), also denoted as GERAN. GERAN is the radio component of GSM/EDGE, together with the network that joins the base stations (for example, the Ater and Abis interfaces) and the base station controllers (A interfaces, etc.). The radio access network represents a component of a GSM network, through which phone calls and packet data are routed from and to the public switched telephone network (PSTN) and Internet to and from subscriber handsets, also known as user terminals or user equipments (UEs). A mobile phone operator's network may comprise one or more GERANs, which may be coupled with UTRANs in the case of a UMTS/GSM network. Additionally, an operator network may also include one or more LTE networks, or one or more other networks. The various different network types may use different radio access technologies (RATs) and RANs.

An OFDMA network may implement a radio technology such as evolved UTRA (E-UTRA), Institute of Electrical and Electronics Engineers (IEEE) 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and the like. UTRA, E-UTRA, and GSM are part of universal mobile telecommunication system (UMTS). In particular, long term evolution (LTE) is a release of UMTS that uses E-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documents provided from an organization named “3rd Generation Partnership Project” (3GPP), and cdma2000 is described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). These various radio technologies and standards are known or are being developed. For example, the 3GPP is a collaboration between groups of telecommunications associations that aims to define a globally applicable third generation (3G) mobile phone specification. 3GPP LTE is a 3GPP project which was aimed at improving UMTS mobile phone standard. The 3GPP may define specifications for the next generation of mobile networks, mobile systems, and mobile devices. The present disclosure may describe certain aspects with reference to LTE, 4G, or 5G NR technologies; however, the description is not intended to be limited to a specific technology or application, and one or more aspects described with reference to one technology may be understood to be applicable to another technology. Additionally, one or more aspects of the present disclosure may be related to shared access to wireless spectrum between networks using different radio access technologies or radio air interfaces.

2 2 5G networks contemplate diverse deployments, diverse spectrum, and diverse services and devices that may be implemented using an OFDM-based unified, air interface. To achieve these goals, further enhancements to LTE and LTE-A are considered in addition to development of the new radio technology for 5G NR networks. The 5G NR will be capable of scaling to provide coverage (1) to a massive Internet of things (IoTs) with an ultra-high density (e.g., ˜1 M nodes/km), ultra-low complexity (e.g., ˜10 s of bits/sec), ultra-low energy (e.g., ˜10+ years of battery life), and deep coverage with the capability to reach challenging locations; (2) including mission-critical control with strong security to safeguard sensitive personal, financial, or classified information, ultra-high reliability (e.g., ˜99.9999% reliability), ultra-low latency (e.g., ˜1 millisecond (ms)), and users with wide ranges of mobility or lack thereof; and (3) with enhanced mobile broadband including extreme high capacity (e.g., ˜10 Tbps/km), extreme data rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates), and deep awareness with advanced discovery and optimizations.

Devices, networks, and systems may be configured to communicate via one or more portions of the electromagnetic spectrum. The electromagnetic spectrum is often subdivided, based on frequency or wavelength, into various classes, bands, channels, etc. In 5G NR two initial operating bands have been identified as frequency range designations FR1 (410 MHz-7.125 GHz) and FR2 (24.25 GHz-52.6 GHz). The frequencies between FR1 and FR2 are often referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to (interchangeably) as a “sub-6 GHz” band in various documents and articles. A similar nomenclature issue sometimes occurs with regard to FR2, which is often referred to (interchangeably) as a “millimeter wave” (mmWave) band in documents and articles, despite being different from the extremely high frequency (EHF) band (30 GHz-300 GHz) which is identified by the International Telecommunications Union (ITU) as a “mm Wave” band.

With the above aspects in mind, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like if used herein may broadly represent frequencies that may be less than 6 GHz, may be within FR1, or may include mid-band frequencies. Further, unless specifically stated otherwise, it should be understood that the term “mm Wave” or the like if used herein may broadly represent frequencies that may include mid-band frequencies, may be within FR2, or may be within the EHF band.

5G NR devices, networks, and systems may be implemented to use optimized OFDM-based waveform features. These features may include scalable numerology and transmission time intervals (TTIs); a common, flexible framework to efficiently multiplex services and features with a dynamic, low-latency time division duplex (TDD) design or frequency division duplex (FDD) design; and advanced wireless technologies, such as massive multiple input, multiple output (MIMO), robust mmWave transmissions, advanced channel coding, and device-centric mobility. Scalability of the numerology in 5G NR, with scaling of subcarrier spacing, may efficiently address operating diverse services across diverse spectrum and diverse deployments. For example, in various outdoor and macro coverage deployments of less than 3 GHz FDD or TDD implementations, subcarrier spacing may occur with 15 kHz, for example over 1, 5, 10, 20 MHz, and the like bandwidth. For other various outdoor and small cell coverage deployments of TDD greater than 3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHz bandwidth. For other various indoor wideband implementations, using a TDD over the unlicensed portion of the 5 GHz band, the subcarrier spacing may occur with 60 kHz over a 160 MHz bandwidth. Finally, for various deployments transmitting with mm Wave components at a TDD of 28 GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz bandwidth.

The scalable numerology of 5G NR facilitates scalable TTI for diverse latency and quality of service (QoS) requirements. For example, shorter TTI may be used for low latency and high reliability, while longer TTI may be used for higher spectral efficiency. The efficient multiplexing of long and short TTIs to allow transmissions to start on symbol boundaries. 5G NR also contemplates a self-contained integrated subframe design with uplink or downlink scheduling information, data, and acknowledgement in the same subframe. The self-contained integrated subframe supports communications in unlicensed or contention-based shared spectrum, adaptive uplink or downlink that may be flexibly configured on a per-cell basis to dynamically switch between uplink and downlink to meet the current traffic needs.

For clarity, certain aspects of the apparatus and techniques may be described below with reference to example 5G NR implementations or in a 5G-centric way, and 5G terminology may be used as illustrative examples in portions of the description below; however, the description is not intended to be limited to 5G applications.

Moreover, it should be understood that, in operation, wireless communication networks adapted according to the concepts herein may operate with any combination of licensed or unlicensed spectrum depending on loading and availability. Accordingly, it will be apparent to a person having ordinary skill in the art that the systems, apparatus and methods described herein may be applied to other communications systems and applications than the particular examples provided.

While aspects and implementations are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, implementations or uses may come about via integrated chip implementations or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail devices or purchasing devices, medical devices, AI-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregated, distributed, or original equipment manufacturer (OEM) devices or systems incorporating one or more described aspects. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described aspects. It is intended that innovations described herein may be practiced in a wide variety of implementations, including both large devices or small devices, chip-level components, multi-component systems (e.g., radio frequency (RF)-chain, communication interface, processor), distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

1 FIG. 1 FIG. 100 100 is a block diagram illustrating details of an example wireless communication system according to one or more aspects. The wireless communication system may include wireless network. Wireless networkmay, for example, include a 5G wireless network. As appreciated by those skilled in the art, components appearing inare likely to have related counterparts in other network arrangements including, for example, cellular-style network arrangements and non-cellular-style-network arrangements (e.g., device to device or peer to peer or ad hoc network arrangements, etc.).

100 105 105 100 105 100 100 105 105 115 105 115 1 FIG. Wireless networkillustrated inincludes a number of base stationsand other network entities. A base station may be a station that communicates with the UEs and may also be referred to as an evolved node B (eNB), a next generation eNB (gNB), an access point, and the like. Each base stationmay provide communication coverage for a particular geographic area. In 3GPP, the term “cell” may refer to this particular geographic coverage area of a base station or a base station subsystem serving the coverage area, depending on the context in which the term is used. In implementations of wireless networkherein, base stationsmay be associated with a same operator or different operators (e.g., wireless networkmay include a plurality of operator wireless networks). Additionally, in implementations of wireless networkherein, base stationmay provide wireless communications using one or more of the same frequencies (e.g., one or more frequency bands in licensed spectrum, unlicensed spectrum, or a combination thereof) as a neighboring cell. In some examples, an individual base stationor UEmay be operated by more than one network operating entity. In some other examples, each base stationand UEmay be operated by a single network operating entity.

1 FIG. 105 105 105 105 105 105 105 d e a c a c f A base station may provide communication coverage for a macro cell or a small cell, such as a pico cell or a femto cell, or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a pico cell, would generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell, such as a femto cell, would also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). A base station for a macro cell may be referred to as a macro base station. A base station for a small cell may be referred to as a small cell base station, a pico base station, a femto base station or a home base station. In the example shown in, base stationsandare regular macro base stations, while base stations-are macro base stations enabled with one of 3 dimension (3D), full dimension (FD), or massive MIMO. Base stations-take advantage of their higher dimension MIMO capabilities to exploit 3D beamforming in both elevation and azimuth beamforming to increase coverage and capacity. Base stationis a small cell base station which may be a home node or portable access point. A base station may support one or multiple (e.g., two, three, four, and the like) cells.

100 Wireless networkmay support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. In some scenarios, networks may be enabled or configured to handle dynamic switching between synchronous or asynchronous operations.

115 100 115 115 115 100 115 115 100 a d e k 1 FIG. 1 FIG. UEsare dispersed throughout the wireless network, and each UE may be stationary or mobile. It should be appreciated that, although a mobile apparatus is commonly referred to as a UE in standards and specifications promulgated by the 3GPP, such apparatus may additionally or otherwise be referred to by those skilled in the art as a mobile station (MS), a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT), a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, a gaming device, an augmented reality device, vehicular component, vehicular device, or vehicular module, or some other suitable terminology. Within the present document, a “mobile” apparatus or UE need not necessarily have a capability to move, and may be stationary. Some non-limiting examples of a mobile apparatus, such as may include implementations of one or more of UEs, include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a laptop, a personal computer (PC), a notebook, a netbook, a smart book, a tablet, and a personal digital assistant (PDA). A mobile apparatus may additionally be an IoT or “Internet of everything” (IoE) device such as an automotive or other transportation vehicle, a satellite radio, a global positioning system (GPS) device, a global navigation satellite system (GNSS) device, a logistics controller, a drone, a multi-copter, a quad-copter, a smart energy or security device, a solar panel or solar array, municipal lighting, water, or other infrastructure; industrial automation and enterprise devices; consumer and wearable devices, such as eyewear, a wearable camera, a smart watch, a health or fitness tracker, a mammal implantable device, gesture tracking device, medical device, a digital audio player (e.g., MP3 player), a camera, a game console, etc.; and digital home or smart home devices such as a home audio, video, and multimedia device, an appliance, a sensor, a vending machine, intelligent lighting, a home security system, a smart meter, etc. In one aspect, a UE may be a device that includes a Universal Integrated Circuit Card (UICC). In another aspect, a UE may be a device that does not include a UICC. In some aspects, UEs that do not include UICCs may also be referred to as IoE devices. UEs-of the implementation illustrated inare examples of mobile smart phone-type devices accessing wireless networkA UE may also be a machine specifically configured for connected communication, including machine type communication (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. UEs-illustrated inare examples of various machines configured for communication that access wireless network.

115 100 1 FIG. A mobile apparatus, such as UEs, may be able to communicate with any type of the base stations, whether macro base stations, pico base stations, femto base stations, relays, and the like. In, a communication link (represented as a lightning bolt) indicates wireless transmissions between a UE and a serving base station, which is a base station designated to serve the UE on the downlink or uplink, or desired transmission between base stations, and backhaul transmissions between base stations. UEs may operate as base stations or other network nodes in some scenarios. Backhaul communication between base stations of wireless networkmay occur using wired or wireless communication links.

100 105 105 115 115 105 105 105 105 105 115 115 a c a b d a c f d c d In operation at wireless network, base stations-serve UEsandusing 3D beamforming and coordinated spatial techniques, such as coordinated multipoint (CoMP) or multi-connectivity. Macro base stationperforms backhaul communications with base stations-, as well as small cell, base station. Macro base stationalso transmits multicast services which are subscribed to and received by UEsand. Such multicast services may include mobile television or stream video, or may include other services for providing community information, such as weather emergencies or alerts, such as Amber alerts or gray alerts.

100 115 115 105 105 105 115 115 115 100 105 105 115 115 105 100 115 115 105 e e d e f f g h f e f g f i k e. Wireless networkof implementations supports mission critical communications with ultra-reliable and redundant links for mission critical devices, such UE, which is a drone. Redundant communication links with UEinclude from macro base stationsand, as well as small cell base station. Other machine type devices, such as UE(thermometer), UE(smart meter), and UE(wearable device) may communicate through wireless networkeither directly with base stations, such as small cell base station, and macro base station, or in multi-hop configurations by communicating with another user device which relays its information to the network, such as UEcommunicating temperature measurement information to the smart meter, UE, which is then reported to the network through small cell base station. Wireless networkmay also provide additional network efficiency through dynamic, low-latency TDD communications or low-latency FDD communications, such as in a vehicle-to-vehicle (V2V) mesh network between UEs-communicating with macro base station

2 FIG. 1 FIG. 1 FIG. 2 FIG. 105 115 105 115 105 105 115 115 115 105 105 105 105 105 234 234 115 252 252 f c d f f f a t a r is a block diagram illustrating examples of base stationand UEaccording to one or more aspects. Base stationand UEmay be any of the base stations and one of the UEs in. For a restricted association scenario (as mentioned above), base stationmay be small cell base stationin, and UEmay be UEoroperating in a service area of base station, which in order to access small cell base station, would be included in a list of accessible UEs for small cell base station. Base stationmay also be a base station of some other type. As shown in, base stationmay be equipped with antennasthrough, and UEmay be equipped with antennasthroughfor facilitating wireless communications.

105 220 212 240 220 220 230 232 232 232 232 232 232 234 234 a t a t a t At base station, transmit processormay receive data from data sourceand control information from controller, such as a processor. The control information may be for a physical broadcast channel (PBCH), a physical control format indicator channel (PCFICH), a physical hybrid-ARQ (automatic repeat request) indicator channel (PHICH), a physical downlink control channel (PDCCH), an enhanced physical downlink control channel (EPDCCH), an MTC physical downlink control channel (MPDCCH), etc. The data may be for a physical downlink shared channel (PDSCH), etc. Additionally, transmit processormay process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. Transmit processormay also generate reference symbols, e.g., for the primary synchronization signal (PSS) and secondary synchronization signal (SSS), and cell-specific reference signal. Transmit (TX) MIMO processormay perform spatial processing (e.g., precoding) on the data symbols, the control symbols, or the reference symbols, if applicable, and may provide output symbol streams to modulators (MODs)through. For example, spatial processing performed on the data symbols, the control symbols, or the reference symbols may include precoding. Each modulatormay process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulatormay additionally or alternatively process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulatorsthroughmay be transmitted via antennasthrough, respectively.

115 252 252 105 254 254 254 254 256 254 254 258 115 260 280 a r a r a r At UE, antennasthroughmay receive the downlink signals from base stationand may provide received signals to demodulators (DEMODs)through, respectively. Each demodulatormay condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulatormay further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. MIMO detectormay obtain received symbols from demodulatorsthrough, perform MIMO detection on the received symbols if applicable, and provide detected symbols. Receive processormay process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UEto data sink, and provide decoded control information to controller, such as a processor.

115 264 262 280 264 264 266 254 254 105 105 115 234 232 236 238 115 238 239 240 a r On the uplink, at UE, transmit processormay receive and process data (e.g., for a physical uplink shared channel (PUSCH)) from data sourceand control information (e.g., for a physical uplink control channel (PUCCH)) from controller. Additionally, transmit processormay also generate reference symbols for a reference signal. The symbols from transmit processormay be precoded by TX MIMO processorif applicable, further processed by modulatorsthrough(e.g., for SC-FDM, etc.), and transmitted to base station. At base station, the uplink signals from UEmay be received by antennas, processed by demodulators, detected by MIMO detectorif applicable, and further processed by receive processorto obtain decoded data and control information sent by UE. Receive processormay provide the decoded data to data sinkand the decoded control information to controller.

240 280 105 115 240 105 280 115 242 282 105 115 244 4 6 FIGS.and Controllersandmay direct the operation at base stationand UE, respectively. Controlleror other processors and modules at base stationor controlleror other processors and modules at UEmay perform or direct the execution of various processes for the techniques described herein, such as to perform or direct the execution illustrated in, or other processes for the techniques described herein. Memoriesandmay store data and program codes for base stationand UE, respectively. Schedulermay schedule UEs for data transmission on the downlink or the uplink.

115 105 115 105 115 105 In some cases, UEand base stationmay operate in a shared radio frequency spectrum band, which may include licensed or unlicensed (e.g., contention-based) frequency spectrum. In an unlicensed frequency portion of the shared radio frequency spectrum band, UEsor base stationsmay traditionally perform a medium-sensing procedure to contend for access to the frequency spectrum. For example, UEor base stationmay perform a listen-before-talk or listen-before-transmitting (LBT) procedure such as a clear channel assessment (CCA) prior to communicating in order to determine whether the shared channel is available. In some implementations, a CCA may include an energy detection procedure to determine whether there are any other active transmissions. For example, a device may infer that a change in a received signal strength indicator (RSSI) of a power meter indicates that a channel is occupied. Specifically, signal power that is concentrated in a certain bandwidth and exceeds a predetermined noise floor may indicate another wireless transmitter. A CCA also may include detection of specific sequences that indicate use of the channel. For example, another device may transmit a specific preamble prior to transmitting a data sequence. In some cases, an LBT procedure may include a wireless node adjusting its own backoff window based on the amount of energy detected on a channel or the acknowledge/negative-acknowledge (ACK/NACK) feedback for its own transmitted packets as a proxy for collisions.

3 FIG. 300 300 100 300 115 105 115 105 300 115 105 is a block diagram of an example wireless communications systemthat supports acquiring TA information for a candidate cell using a sounding reference signal (SRS) according to one or more aspects. In some examples, wireless communications systemmay implement aspects of wireless network. Wireless communications systemincludes UEand base station. Although one UEand one base stationare illustrated, in some other implementations, wireless communications systemmay generally include multiple UEs, and may include more than one base station.

115 302 302 304 304 316 316 318 318 302 304 302 258 264 280 304 282 UEmay include a variety of components (such as structural, hardware components) used for carrying out one or more functions described herein. For example, these components may include one or more processors(hereinafter referred to collectively as “processor”), one or more memory devices(hereinafter referred to collectively as “memory”), one or more transmitters(hereinafter referred to collectively as “transmitter”), and one or more receivers(hereinafter referred to collectively as “receiver”). Processormay be configured to execute instructions stored in memoryto perform the operations described herein. In some implementations, processorincludes or corresponds to one or more of receive processor, transmit processor, and controller, and memoryincludes or corresponds to memory.

304 305 320 322 324 332 338 342 334 340 344 336 346 324 326 328 330 Memoryincludes or is configured to store information, an indication, an SRS set, an SRS, an initial TA, a timing difference, a TA indication, an initial transmit power, a power difference, a transmit power indication, an initial beam, and a beam indication. The SRSincludes TA information, transmit power information, and beam information.

316 318 316 318 105 316 318 316 318 115 2 FIG. Transmitteris configured to transmit reference signals, control information and data to one or more other devices, and receiveris configured to receive references signals, synchronization signals, control information and data from one or more other devices. For example, transmittermay transmit signaling, control information and data to, and receivermay receive signaling, control information and data from, base station. In some implementations, transmitterand receivermay be integrated in one or more transceivers. Additionally or alternatively, transmitteror receivermay include or correspond to one or more components of UEdescribed with reference to.

105 352 352 354 354 356 356 358 358 352 354 352 238 220 240 354 242 Base stationmay include a variety of components (such as structural, hardware components) used for carrying out one or more functions described herein. For example, these components may include one or more processors(hereinafter referred to collectively as “processor”), one or more memory devices(hereinafter referred to collectively as “memory”), one or more transmitters(hereinafter referred to collectively as “transmitter”), and one or more receivers(hereinafter referred to collectively as “receiver”). Processormay be configured to execute instructions stored in memoryto perform the operations described herein. In some implementations, processorincludes or corresponds to one or more of receive processor, transmit processor, and controller, and memoryincludes or corresponds to memory.

354 360 362 Memoryincludes or is configured to store informationand an SRS.

356 358 356 358 115 356 358 356 358 105 2 FIG. Transmitteris configured to transmit reference signals, synchronization signals, control information and data to one or more other devices, and receiveris configured to receive reference signals, control information and data from one or more other devices. For example, transmittermay transmit signaling, control information and data to, and receivermay receive signaling, control information and data from, UE. In some implementations, transmitterand receivermay be integrated in one or more transceivers. Additionally or alternatively, transmitteror receivermay include or correspond to one or more components of base stationdescribed with reference to.

300 300 115 105 In some implementations, wireless communications systemimplements a 5G NR network. For example, wireless communications systemmay include multiple 5G-capable UEsand multiple 5G-capable base stations, such as UEs and base stations configured to operate in accordance with a 5G NR network protocol such as that defined by the 3GPP.

300 115 320 115 320 105 115 115 115 115 105 115 115 326 330 328 During operation of wireless communications system, the UEmay be configured to receive an indicationof a candidate cell. In particular, the UEmay be transitioning from communicating with an active cell to the candidate cell, and the indicationmay identify the candidate cell. In certain implementations, cells may include or otherwise be implemented by a base station, such as the base station. In additional or alternative implementations, cells may include a portion of a service area for a base station. In certain implementations, the candidate cell may include a cell (such as a PCell, SCell, PSCell, SpCell, or combinations thereof) with which the UEmay be not currently communicating. For example, the UEmay be transitioning from a current, active cell to a new, candidate cell, such as in an L1/L2 mobility scenario. The candidate cell may be a cell selected as the next cell with which the UEwill communicate. For example, the UEmay be transitioning from an active cell implemented by a base station (not depicted) to a candidate cell implemented by the base station. In certain implementations, multiple cells may be capable of communicating with the UEas the UEmoves. In such instances, the candidate cell may include multiple candidate cells. In such instances, the present techniques may be performed to identify information (such as TA information, beam information, transmit power information, or combinations thereof) for use in communicating with at least a subset of the multiple candidate cells.

115 322 326 326 115 115 105 326 115 105 322 115 105 322 115 322 322 322 326 The UEmay be configured to determine, based on an SRS set, timing advance (TA) informationfor communication with the candidate cell. In certain implementations, TA informationmay indicate a timing offset that the UEapplies to transmissions between the UEand the candidate cell (such as the base station). In particular, the TA informationmay indicate how much the UEneeds to advance uplink transmissions sent to the base station. The SRS setmay identify information regarding SRS communications between the UEand the base station. In certain implementations, the SRS setmay be predetermined and may be previously stored on the UE. In certain implementations, the SRS setmay be a dedicated SRS setfor TA management in a candidate cell. In certain implementations, the dedicated SRS setfor TA management only contains TA informationor other timing information for one or more candidate cells.

322 320 322 322 115 115 322 115 322 In certain implementations, the SRS setmay be identified as corresponding to the candidate cell. In certain implementations, the indicationor other identifier of the candidate cell may correspond to the SRS set(such as one or multiple predetermined SRS setsstored by the UE). For example, the UEmay be configured to utilize separate SRS setsfor individual candidate cells. For example, the UEmay be configured to identify 4 candidate cells when transitioning between cells and may store separate SRS setsfor each candidate cell.

322 115 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 322 In certain implementations, the SRS setmay be configured by or based on the active cell and received by the UEwith the signaling from the active cell. In certain implementations, the SRS setmay be determined based on a previous SRS setfor the active cell, the previous SRS setmay include an SRS setconfigured under the serving cell but associated with the candidate cell for codebook based MIMO, an SRS setfor non-codebook based MIMO, an SRS setfor positioning, an SRS setfor beam management, or combinations thereof. In certain implementations, the SRS setmay be determined based on the SRS setfor positioning configured under an active cell (such as a serving cell) but associated with the candidate cell. In certain implementations, the SRS setmay be a modified version of the previous SRS set. For example, the SRS setmay be altered based on a predefined update protocol for the previous SRS set(such as a preconfigured update protocol). In certain implementations, the SRS setmay be updated according to a periodic transmission, a semi-persistent transmission, an aperiodic transmission, or combinations thereof. In certain implementations, the SRS setmay define an inter-frequency SRS with at least one of a different frequency from the previous SRS set, a different sub-carrier spacing (SCS) from the previous SRS set, a different bandwidth part (BWP) from the previous SRS set, or combinations thereof.

326 322 320 326 322 115 322 115 326 322 320 In certain implementations, the TA informationmay be identified as corresponding to the candidate cell within the SRS set. In certain implementations, the indicationor identifier of the candidate cell may correspond to the TA informationwithin the SRS set. For example, the UEmay be configured to identify four candidate cells and may include a single SRS setthat contains four separate SRS resources for the four candidate cells. In such instances, the UEmay identify the TA informationbased on corresponding information for the four SRS resources within the SRS set, such as the beam indicationof the candidate cell.

115 324 326 326 332 324 326 332 324 332 342 115 342 115 342 115 115 326 324 332 324 332 115 332 320 115 The UEmay be configured to transmit, to the candidate cell, an SRSthat includes the TA information. In certain implementations, the TA informationmay include an initial TAfor use in communicating with the candidate cell. In such instances, transmitting the SRSto the candidate cell may include applying the TA information(such as the initial TA) to the SRS. In certain implementations, the initial TAmay be identified based on a TA indicationin a physical downlink control channel (PDCCH) signal received by the UE, a TA indicationin a medium access control (MAC) control element (CE) (“MAC-CE”) signal received by the UE, a TA indicationreceived in a radio resource control (RRC) indication received by the UE, or combinations thereof. In certain implementations, the UEmay receive a PDCCH and, in response to the PDCCH, may determine the TA informationand transmit the SRSto the candidate cell. In such instances, the initial TAmay be identified from the PDCCH for use in transmitting the SRS. In additional or alternative implementations, the initial TAmay be contained in another message received by the UE, such as the MAC-CE or an RRC message. In certain implementations, such communications may be received from the active cell or another network component in the network, such as a gNodeB. In certain implementations, the initial TAindicationmay be received before, within, or after a cell switching command received by the UE(such as a cell switching command to switch from the active cell to the candidate cell).

115 370 105 115 338 332 338 338 338 115 332 338 115 338 332 338 115 332 In certain implementations, the UEmay determine the TA information based on measurements of a messagereceived from the base station. For example, the UEmay be configured to receive a first communication from the candidate cell, determine a timing differencebetween the first communication and a second communication received from the active cell, and determine the initial TAbased on the timing difference. In certain implementations, the timing differencemay include a receive-side timing difference between the first communication and the second communication. The timing differencemay include or otherwise be determined based on a difference in reception time between the first communication and the second communication. In certain implementations, the UEmay determine the initial TAto compensate for the timing difference. In particular, the UEmay apply the timing differenceto a previous TA used for communicating with the active cell to determine the initial TAfor the candidate cell. Such implementations based on timing differencesmay be used for instances where the UEdoes not receive an initial TAIndication from a gNodeB.

324 326 324 330 328 324 334 324 334 324 334 344 115 344 115 344 320 115 115 326 334 324 328 105 334 344 334 115 344 344 344 115 In certain implementations, the SRSmay include additional information beyond the TA information. For example, the SRSmay specify beam information(such as beam management information), transmit power information, or combinations thereof. In certain implementations, the SRSfurther may include an initial transmit powerfor use in communicating with the candidate cell. In such instances, transmitting the SRSto the candidate cell may include applying the initial transmit powerto the SRS. In certain implementations, the initial transmit powermay be identified based on a transmit power indicationin a PDCCH received by the UE, a transmit power indicationin a MAC-CE received by the UE, a transmit power indicationreceived in an RRC indicationreceived by the UE, or combinations thereof. In certain implementations, the UEmay receive a PDCCH and, in response to the PDCCH, may determine the TA information, determine the initial transmit power, and transmit the SRScontaining power informationto the candidate cell (such as to the base station). In such instances, the initial transmit powermay be identified from the PDCCH (such as from a transmit power indicationwithin the PDCCH). In additional or alternative implementations, the initial transmit powermay be contained in another message received by the UE, such as the MAC-CE or an RRC message (such as in a transmit power indicationcontained in such messages). In certain implementations, such communications may be received from the active cell or another network component in the network, such as a gNodeB. In certain implementations, the transmit power indicationmay include a target received power, a close loop index, an alpha value, a transmit power command, a power delta value, or combinations thereof. In certain implementations, the initial transmit power indicationmay be received before, within, or after a cell switching command received by the UE(such as a cell switching command to switch from the active cell to the candidate cell).

115 334 115 340 334 340 340 115 332 115 340 334 340 115 344 In certain implementations, the UEmay be configured to determine the initial transmit powerbased on one or more signal measurements. For example, the UEmay be configured to receive a first communication from the candidate cell, determine a power differencebetween the first communication and a second communication received from the active cell, and determine the initial transmit powerbased on the power difference. In certain implementations, the power differencemay include a path loss difference between the first and second communications, such as a difference in received power between the first communication and the second communication. In certain implementations, the UEmay determine the initial TAto compensate for the path loss difference. In particular, the UEmay apply the power differenceto a previous transmit power used for communicating with the active cell to determine the initial transmit powerfor the candidate cell. Such implementations based on power differencemay be used for instances where the UEdoes not receive an initial transmit power indicationfrom a gNodeB.

324 336 324 336 336 346 115 346 115 346 320 115 115 326 336 324 336 324 336 115 346 346 346 115 In certain implementations, the SRSfurther may include an initial beamfor use in communicating with the candidate cell. In such instances, the SRSmay be transmitted to the candidate cell using the initial beam. In certain implementations, the initial beammay be identified based on a beam indicationin a PDCCH received by the UE, a beam indicationin a MAC-CE received by the UE, a beam indicationreceived in an RRC indicationreceived by the UE, or combinations thereof. In certain implementations, the UEmay receive a PDCCH and, in response to the PDCCH, may determine the TA information, determine the initial beam, and transmit the SRSto the candidate cell. In such instances, the initial beammay be identified from the PDCCH for use in transmitting the SRS. In additional or alternative implementations, the initial beammay be contained in another message received by the UE, such as the MAC-CE or an RRC message, such as in a beam indicationcontained in the message. In certain implementations, such communications may be received from the active cell or another network component in the network, such as a gNodeB. In certain implementations, the beam indicationmay include a unified transmission configuration indicator (TCI) (such as a joint TCI, an uplink TCI, or combinations thereof), legacy spatial relation information, or combinations thereof. In certain implementations, the beam indicationmay be received before, within, or after a cell switching command received by the UE(such as a cell switching command to switch from the active cell to the candidate cell).

115 324 326 330 328 324 115 326 In certain implementations, the UEand the candidate cell may continue communicating according to the SRS(such as according to the TA information, beam information, transmit power information, or combinations thereof identified by the SRS). In additional or alternative implementations, the UEand the candidate cell may subsequently communicate to establish updated TA informationfor future communications.

115 105 5 FIG. The above techniques were discussed as being performed by the UE. In various implementation, one skilled in the art will appreciate that all or part of these techniques may be performed by a base station, such as by the candidate cell. For example, such implementations are discussed in greater detail in connection withbelow.

3 FIG. As described with reference to, the present disclosure provides techniques for acquiring uplink timing information, such as TA information, by SRS transmission in ways that reduce the communicative overhead, complexity, and uplink resources. This information may be further refined to additionally improve the quality and efficiency of communication with candidate cells.

4 FIG. 1 2 3 FIGS.,, 5 FIG. 400 324 400 115 115 115 115 400 115 324 is a flow diagram illustrating an example processthat supports acquiring TA information for a candidate cell using an SRSaccording to one or more aspects. Operations of processmay be performed by a UE, such as UEdescribed above with reference to, or a UEdescribed with reference to. For example, example operations (also referred to as “blocks”) of processmay enable UEto support acquiring TA information for a candidate cell using an SRS.

400 402 115 320 115 320 The processincludes receiving an indication of a candidate cell (block). For example, the UEmay receive an indicationof a candidate cell. The UEmay be transitioning from communicating with an active cell to the candidate cell and may receive the indicationas part of the transition, such as in an L1/L2 mobility scenario.

400 404 115 322 326 322 115 322 320 322 322 115 322 322 322 115 322 322 322 322 322 322 322 322 322 322 322 322 320 326 322 The processincludes determining, based on an SRS set, timing advance (TA) information for communication with the candidate cell (block). For example, the UEmay determine, based on an SRS set, TA informationfor communication with the candidate cell. In certain implementations, the SRS setmay be predetermined and previously stored on the UE. In certain implementations, the SRS setmay be identified as corresponding to the candidate cell. For example, the indicationor other identifier of the candidate cell may correspond to the SRS set(such as one or multiple predetermined SRS setsstored by the UE). The SRS setmay be a dedicated SRS setfor TA management. In certain implementations, the SRS setmay be configured by or based on the active cell and received by the UEfrom the active cell. For example, the SRS setmay be determined based on a previous SRS setfor the active cell, such as an SRS setfor codebook based MIMO with the active cell, an SRS setfor non-codebook based MIMO with the active cell, an SRS setfor positioning with the active cell, an SRS setfor beam management with the active cell, or combinations thereof. For example, the SRS setmay be determined based on the SRS setfor positioning with the active cell. In certain implementations, the SRS setmay be a modified version of the previous SRS set. For example, the SRS setmay be altered based on a predefined update protocol for the previous SRS set(such as a preconfigured update protocol). In certain implementations, the indicationor another identifier of the candidate cell may correspond to the TA informationwithin the SRS set.

400 406 115 324 326 326 332 324 326 324 332 320 115 320 115 320 320 115 338 332 338 338 338 332 338 The processincludes transmitting, to the candidate cell, an SRS that includes the TA information (block). For example, the UEmay transmit, to the candidate cell, an SRSthat includes the TA information. In certain implementations, the TA informationmay include an initial TAfor use in communicating with the candidate cell. In such instances, transmitting the SRSto the candidate cell may include applying the TA informationto the SRS. In certain implementations, the initial TAmay be identified based on a TA indicationin a PDCCH received by the UE, a TA indicationin a MAC-CE received by the UE, a TA indicationreceived in an RRC indicationreceived by the UE, or combinations thereof. In certain implementations, the method may further include receiving a first communication from the candidate cell, determining a timing differencebetween the first communication and a second communication received from the active cell, and determining the initial TAbased on the timing difference. For example, the timing differencemay include a receive-side timing differencebetween the first communication and the second communication and the initial TAmay be determined to compensate for the timing difference.

324 326 324 330 328 324 334 324 334 324 334 344 115 344 115 344 115 340 334 340 115 334 340 In certain implementations, the SRSmay include additional information beyond the TA information. For example, the SRSmay specify beam information, power information, or combinations thereof. For example, the SRSmay include an initial transmit powerfor use in communicating with the candidate cell. In such instances, transmitting the SRSto the candidate cell may include applying the initial transmit powerto the SRS. In certain implementations, the initial transmit powermay be identified based on a transmit power indicationin a PDCCH received by the UE, a transmit power indicationin a MAC-CE received by the UE, a transmit power indicationin an RRC indication received by the UE, or combinations thereof. In certain implementations, the method may further include receiving a first communication from the candidate cell, determining a power differencebetween the first communication and a second communication received from the active cell, and determining the initial transmit powerbased on the power difference. For example, the UEmay determine the initial transmit powerto compensate for the power difference.

324 336 324 336 336 346 115 346 115 346 320 115 346 In certain implementations, the SRSfurther may include an initial beamfor use in communicating with the candidate cell. In such instances, the SRSmay be transmitted to the candidate cell using the initial beam. In certain implementations, the initial beammay be identified based on a beam indicationin a PDCCH received by the UE, a beam indicationin a MAC-CE received by the UE, a beam indicationin an RRC indicationreceived by the UE, or combinations thereof. For example, the beam indicationmay include a unified TCI legacy spatial relation information, or combinations thereof.

115 115 324 326 330 328 324 115 326 The UEand the candidate cell may continuecommunicating according to the SRS(such as according to the TA information, beam information, transmit power information, or combinations thereof identified by the SRS). In additional or alternative implementations, the UEand the candidate cell may subsequently communicate to establish updated TA informationfor future communications.

5 FIG. 4 6 FIG.or 1 3 FIGS.- 2 FIG. 1 3 FIGS.- 7 FIG. 500 324 500 500 115 500 280 282 500 500 500 280 501 252 501 115 254 256 258 264 266 500 105 a r a r a r a r is a block diagram of an example UEthat supports acquiring TA information for a candidate cell using an SRSto one or more aspects. UEmay be configured to perform operations, including the blocks of a process described with reference to. In some implementations, UEincludes the structure, hardware, and components shown and described with reference to UEof. For example, UEincludes controller, which operates to execute logic or computer instructions stored in memory, as well as controlling the components of UEthat provide the features and functionality of UE. UE, under control of controller, transmits and receives signals via wireless radios-and antennas-. Wireless radios-include various components and hardware, as illustrated infor UE, including modulator and demodulators-, MIMO detector, receive processor, transmit processor, and TX MIMO processor. UEmay receive signals from or transmit signals to one or more network entities, such as base stationofor a base station as illustrated in.

282 502 503 504 505 503 503 501 252 320 500 320 a r a r As shown, memorymay include information, candidate cell identification logic, TA information determining logic, and SRS transmitting logic. The candidate cell identification logicmay be configured to receive an indication of a candidate cell. For example, the candidate cell identification logicmay receive, via the wireless radios-and antennas-, an indicationof a candidate cell. The UEmay be transitioning from communicating with an active cell to the candidate cell and may receive the indicationas part of the transition, such as in an L1/L2 mobility scenario.

504 504 322 326 322 115 322 322 115 322 322 322 322 322 322 320 326 322 The TA information determining logicmay be configured to determine, based on an SRS set, TA information for communication with the candidate cell. For example, the TA information determining logicmay determine, based on an SRS set, TA informationfor communication with the candidate cell. In certain implementations, the SRS setmay be predetermined and previously stored on the UE. In certain implementations, the SRS setmay be identified as corresponding to the candidate cell. In certain implementations, the SRS setmay be defined by the active cell and received by the UEfrom the active cell. For example, the SRS setmay be determined based on a previous SRS setfor the active cell. In certain implementations, the SRS setmay be a modified version of the previous SRS set. For example, the SRS setmay be altered based on a predefined update protocol for the previous SRS set(such as a preconfigured update protocol). In certain implementations, the indicationor another identifier of the candidate cell may correspond to the TA informationwithin the SRS set.

505 406 115 501 252 324 326 326 332 324 326 324 332 320 500 332 504 500 a r a r The SRS transmitting logicmay be configured to transmit, to the candidate cell, an SRS that includes the TA information (block). For example, the UEmay transmit, wireless radios-and antennas-an SRSto the candidate cell that includes the TA information. In certain implementations, the TA informationmay include an initial TAfor use in communicating with the candidate cell. In such instances, transmitting the SRSto the candidate cell may include applying the TA informationto the SRS. In certain implementations, the initial TAmay be identified based on a TA indicationreceived by the UE. For example, the initial TAmay be determined by the TA information determining logicbased on one or more messages received by the UE, as explained further above.

324 326 324 330 328 504 500 330 328 In certain implementations, the SRSmay include additional information beyond the TA information. For example, the SRSmay specify beam information, power information, or combinations thereof. In such implementations, the TA information determining logic, or other logic of the UEmay be configured to determine the additional information,based on one or more received messages, as explained further above.

6 FIG. 1 3 FIGS.- 7 FIG. 600 324 600 105 600 105 324 is a flow diagram illustrating an example processthat supports acquiring TA information for a candidate cell using an SRSaccording to one or more aspects. Operations of processmay be performed by a base station, such as base stationdescribed above with reference toor a base station as described above with reference to. For example, example operations of processmay enable base stationto support acquiring TA information for a candidate cell using an SRS.

600 602 105 320 115 115 105 105 The processincludes receiving an indication of a UE (block). For example, the base stationmay receive an indicationof a UE. The UEmay be transitioning from communicating with a second base stationto the first base station.

600 604 105 322 115 322 322 115 322 322 322 105 322 322 322 322 322 322 322 322 322 105 326 105 322 The processincludes determining, based on an SRS set, timing advance (TA) information for communication with the UE (block). For example, the base stationmay determine, based on an SRS set, TA information for communication with the UE. In certain implementations, the SRS setmay be predetermined and previously stored on the first base station. In certain implementations, the SRS setmay be identified as corresponding to the UE. In certain implementations, the SRS setmay be a dedicated SRS setfor TA management. In certain implementations, the SRS setmay be defined by the second base station and may be received by the first base stationfrom the second base station. In certain implementations, the SRS setmay be determined based on a previous SRS setfor the second base station, the previous SRS setmay include an SRS setfor codebook based MIMO with the second base station, an SRS setfor non-codebook based MIMO with the second base station, an SRS setfor positioning with the second base station, an SRS setfor beam management with the second base station, or combinations thereof. For example, the SRS setmay be determined based on the SRS setfor positioning with second first base station. In certain implementations, the TA informationmay be identified as corresponding to the first base stationwithin the SRS set.

600 606 105 115 324 326 326 332 115 105 324 115 326 324 332 320 105 320 105 320 320 105 The processincludes transmitting, to the UE, an SRS that includes the TA information (block). For example, the base stationmay transmit, to the UE, an SRSthat includes the TA information. In certain implementations, the TA informationmay include an initial TAfor use in communicating between the UEand the first base station. In such instances, transmitting the SRSto the UEmay include applying the TA informationto the SRS. In certain implementations, the initial TAmay be identified based on a TA indicationin a PDCCH received by the first base station, a TA indicationin a MAC-CE received by the first base station, a TA indicationreceived in an RRC indicationreceived by the first base station, or combinations thereof.

324 334 115 324 115 334 324 334 320 344 105 320 344 105 320 344 320 105 In certain implementations, the SRSfurther may include an initial transmit powerfor use in communicating with the UE. In such instances, transmitting the SRSto the UEmay include applying the initial transmit powerto the SRS. In certain implementations, the initial transmit powermay be identified based on a transmit power indicationin a PDCCH received by the first base station, a transmit power indicationin a MAC-CE received by the first base station, a transmit power indicationin an RRC indicationreceived by the first base station, or combinations thereof.

324 336 115 324 115 336 336 320 346 105 320 346 105 346 320 105 In certain implementations, the SRSmay further include an initial beamfor use in communicating with the UE. In such instances, the SRSmay be transmitted to the UEusing the initial beam. In certain implementations, the initial beammay be identified based on a beam indicationin a PDCCH received by the first base station, a beam indicationin a MAC-CE received by the first base station, a beam indicationin an RRC indicationreceived by the first base station, or combinations thereof.

7 FIG. 4 6 FIG.or 1 3 FIGS.- 2 FIG. 700 324 700 600 700 105 700 240 242 700 700 700 240 701 734 701 105 232 220 230 236 238 a t a t a t a t is a block diagram of an example base stationthat supports acquiring TA information for a candidate cell using an SRSaccording to one or more aspects. Base stationmay be configured to perform operations, including the blocks of processdescribed with reference to. In some implementations, base stationincludes the structure, hardware, and components shown and described with reference to base stationof. For example, base stationmay include controller, which operates to execute logic or computer instructions stored in memory, as well as controlling the components of base stationthat provide the features and functionality of base station. Base station, under control of controller, transmits and receives signals via wireless radios-and antennas-. Wireless radios-include various components and hardware, as illustrated infor base station, including modulator and demodulators-, transmit processor, TX MIMO processor, MIMO detector, and receive processor.

242 702 703 704 705 703 703 320 115 500 115 500 700 As shown, memorymay include information, UE identification logic, TA information determining logic, and SRS transmitting logic. The UE identification logicmay be configured to receive an indication of a UE. For example, the candidate cell identification logicmay receive an indicationof a UE,. The UE,may be transitioning from communicating with a second base station to the base station.

704 704 322 326 115 322 700 322 115 322 322 322 700 322 322 322 322 322 322 322 322 322 326 700 322 The TA information determining logicmay be configured to determine, based on an SRS set, TA information for communication with the UE. For example, the TA information determining logicmay determine, based on an SRS set, TA informationfor communication with the UE. In certain implementations, the SRS setmay be predetermined and previously stored on the base station. In certain implementations, the SRS setmay be identified as corresponding to the UE. In certain implementations, the SRS setmay be a dedicated SRS setfor TA management. In certain implementations, the SRS setmay be defined by the second base station and may be received by the base stationfrom the second base station. In certain implementations, the SRS setmay be determined based on a previous SRS setfor the second base station, the previous SRS setmay include an SRS setfor codebook based MIMO with the second base station, an SRS setfor non-codebook based MIMO with the second base station, an SRS setfor positioning with the second base station, an SRS setfor beam management with the second base station, or combinations thereof. For example, the SRS setmay be determined based on the SRS setfor positioning with second base station. In certain implementations, the TA informationmay be identified as corresponding to the first base stationwithin the SRS set.

705 105 115 500 324 326 326 332 115 500 700 324 115 500 326 324 332 320 700 320 700 320 320 700 324 326 324 330 328 704 700 330 328 The SRS transmitting logicmay be configured to transmit, to the UE, an SRS that includes the TA information. For example, the base stationmay transmit, to the UE,, an SRSthat includes the TA information. In certain implementations, the TA informationmay include an initial TAfor use in communicating between the UE,and the first base station. In such instances, transmitting the SRSto the UE,may include applying the TA informationto the SRS. In certain implementations, the initial TAmay be identified based on a TA indicationin a PDCCH received by the first base station, a TA indicationin a MAC-CE received by the first base station, a TA indicationreceived in an RRC indicationreceived by the first base station, or combinations thereof. In certain implementations, the SRSmay include additional information beyond the TA information. For example, the SRSmay specify beam information, power information, or combinations thereof. In such implementations, the TA information determining logic, or other logic of the base stationmay be configured to determine the additional information,based on one or more received messages, as explained further above.

4 6 FIG.or 4 FIG. 6 FIG. 6 FIG. 4 FIG. 4 6 FIGS.and 1 3 FIGS.- 1 3 FIGS.- 5 7 FIG.or It is noted that one or more blocks (or operations) described with reference tomay be combined with one or more blocks (or operations) described with reference to another of the figures. For example, one or more blocks (or operations) ofmay be combined with one or more blocks (or operations) of. As another example, one or more blocks associated withmay be combined with one or more blocks associated with. As another example, one or more blocks associated withmay be combined with one or more blocks (or operations) associated with. Additionally, or alternatively, one or more operations described above with reference tomay be combined with one or more operations described with reference to.

In one or more aspects, techniques for supporting acquiring TA information for a candidate cell using an SRS may include additional aspects, such as any single aspect or any combination of aspects described below or in connection with one or more other processes or devices described elsewhere herein. In a first aspect, the techniques described herein relate to a method of wireless communication performed by a user equipment (UE), the method including receiving an indication of a candidate cell, wherein the UE is transitioning from communicating with an active cell to the candidate cell; determining, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the candidate cell; and transmitting, to the candidate cell, an SRS that includes the TA information.

In a second aspect according to the first aspect, the TA information includes an initial TA for use in communicating with the candidate cell, and wherein transmitting the SRS to the candidate cell includes applying the TA information to the SRS.

In a third aspect according to the second aspect, the initial TA is identified based on a first TA indication in a PDCCH received by the UE, a second TA indication in a MAC-CE received by the UE, a third TA indication received in an RRC indication received by the UE, or combinations thereof.

In a fourth aspect according to at least one of the second through third aspects, the method further includes receiving a first communication from the candidate cell, determining a timing difference between the first communication and a second communication received from the active cell, and determining the initial TA based on the timing difference.

In a fifth aspect according to at least one of the first through fourth aspects, the SRS further includes an initial transmit power for use in communicating with the candidate cell, and wherein transmitting the SRS to the candidate cell includes applying the initial transmit power to the SRS.

In a sixth aspect according to the fifth aspect, the initial transmit power is identified based on a first transmit power indication in a physical downlink control channel (PDCCH) received by the UE, a second transmit power indication in a medium access control (MAC) control element (MAC-CE) received by the UE, a third transmit power indication received in a radio resource control (RRC) indication received by the UE, or combinations thereof.

In a seventh aspect according to at least one of the fifth through sixth aspects, the method further includes receiving a first communication from the candidate cell; determining a path loss difference between the first communication and a second communication received from the active cell; and determining the initial transmit power based on the path loss difference.

In an eighth aspect according to at least one of the first through seventh aspects, the SRS further includes an initial beam for use in communicating with the candidate cell, and wherein the SRS is transmitted to the candidate cell using the initial beam.

In a ninth aspect according to the eighth aspect, the initial beam is identified based on a first beam indication in a PDCCH received by the UE, a second beam indication in a MAC-CE received by the UE, a third beam indication received in an RRC indication received by the UE, or combinations thereof.

In a tenth aspect according to at least one of the first through ninth aspects, the SRS set is predetermined and previously stored on the UE.

In a eleventh aspect according to at least one of the first through tenth aspects, the SRS set is identified as corresponding to the candidate cell.

In a twelfth aspect according to at least one of the first through eleventh aspects, the SRS set is a dedicated SRS set for TA management.

In a thirteenth aspect according to at least one of the first through twelfth aspects, the SRS set is determined by the active cell and received by the UE from the active cell.

In a fourteenth aspect according to the thirteenth aspect, the SRS set is determined based on a previous SRS set for the active cell, wherein the previous SRS set includes a first previous SRS set for codebook based MIMO with the active cell, a second previous SRS set for non-codebook based MIMO with the active cell, a third previous SRS set for positioning with the active cell, an SRS set for beam management with the active cell, or combinations thereof.

In a fifteenth aspect according to the fourteenth aspect, the SRS set is determined based on the third previous SRS set for positioning with the active cell.

In a sixteenth aspect according to at least one of the first through fifteenth aspects, the TA information is identified as corresponding to the candidate cell within the SRS set.

In a seventeenth aspect, the techniques described herein relate to a method of wireless communication performed by a first base station, the method including receiving an indication of a UE, wherein the UE is transitioning from communicating with a second base station to the first base station; determining, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the UE; and transmitting, to the UE, an SRS that includes the TA information.

In an eighteenth aspect according to seventeenth aspect, the TA information includes an initial TA for use in communicating with the first base station, and wherein transmitting the SRS to the UE includes applying the TA information to the SRS.

In a nineteenth aspect according to at least one of the seventeenth through eighteenth aspects, the SRS further includes an initial transmit power for use in communicating with the UE, and wherein transmitting the SRS to the UE includes applying the initial transmit power to the SRS.

In a twentieth aspect according to at least one of the seventeenth through nineteenth aspects, the SRS further includes an initial beam for use in communicating with the UE, and wherein the SRS is transmitted to the UE using the initial beam.

In a twenty-first aspect according to at least one of the seventeenth through twentieth aspects, the SRS set is identified as corresponding to the UE.

In a twenty-second aspect according to at least one of the seventeenth through twenty-second aspects, the SRS set is predetermined and previously stored on the first base station.

In a twenty-third aspect, the techniques described herein relate to a user equipment (UE) including a memory storing processor-readable code; and at least one processor coupled to the memory, the at least one processor configured to execute the processor-readable code to cause the at least one processor to receive an indication of a candidate cell, wherein the UE is transitioning from communicating with an active cell to the candidate cell; determine, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the candidate cell; and transmit, to the candidate cell, an SRS that includes the TA information. Additionally, the apparatus may perform or operate according to one or more aspects as described below. In some implementations, the apparatus includes a wireless device, such as a UE. In some implementations, the apparatus may include at least one processor, and a memory coupled to the processor. The processor may be configured to perform operations described herein with respect to the apparatus. In some other implementations, the apparatus may include a non-transitory computer-readable medium having program code recorded thereon and the program code may be executable by a computer for causing the computer to perform operations described herein with reference to the apparatus. In some implementations, the apparatus may include one or more means configured to perform operations described herein. In some implementations, a method of wireless communication may include one or more operations described herein with reference to the apparatus.

In a twenty-fourth aspect to the twenty-second aspect, the TA information includes an initial TA for use in communicating with the candidate cell, and wherein transmitting the SRS to the candidate cell includes applying the TA information to the SRS.

In a twenty-fifth aspect according to the twenty-fourth aspect, executing the processor-readable code further causes the at least one processor to receive a first communication from the candidate cell; determine a timing difference between the first communication and a second communication received from the active cell; and determine the initial TA based on the timing difference.

In a twenty-sixth aspect according to any one of the twenty-third through twenty-fifth aspects, the SRS further includes an initial transmit power for use in communicating with the candidate cell, and wherein transmitting the SRS to the candidate cell includes applying the initial transmit power to the SRS.

In a twenty-seventh aspect according to any one of the twenty-third through twenty-sixth aspects, the SRS further includes an initial beam for use in communicating with the candidate cell, and the SRS is transmitted to the candidate cell using the initial beam.

In a twenty-eighth aspect, the techniques described herein relate to a first base station including a memory storing processor-readable code; and at least one processor coupled to the memory, the at least one processor configured to execute the processor-readable code to cause the at least one processor to receive an indication of a UE, wherein the UE is transitioning from communicating with a second base station to the first base station; determine, based on a sounding reference signal (SRS) set, timing advance (TA) information for communication with the UE; and transmit, to the UE, an SRS that includes the TA information. Additionally, the apparatus may perform or operate according to one or more aspects as described below. In some implementations, the apparatus includes a wireless device, such as a base station. In some implementations, the apparatus may include at least one processor, and a memory coupled to the processor. The processor may be configured to perform operations described herein with respect to the apparatus. In some other implementations, the apparatus may include a non-transitory computer-readable medium having program code recorded thereon and the program code may be executable by a computer for causing the computer to perform operations described herein with reference to the apparatus. In some implementations, the apparatus may include one or more means configured to perform operations described herein. In some implementations, a method of wireless communication may include one or more operations described herein with reference to the apparatus.

In a twenty-ninth aspect according to the twenty-eighth aspect, the TA information includes an initial TA for use in communicating with the first base station, and wherein transmitting the SRS to the UE includes applying the TA information to the SRS.

In a thirtieth aspect according to any one of the twenty-eighth through twenty-ninth aspects, the SRS further includes an initial transmit power for use in communicating with the UE, and wherein transmitting the SRS to the UE includes applying the initial transmit power to the SRS.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

1 3 5 7 FIGS.-,, and Components, the functional blocks, and the modules described herein with respect toinclude processors, electronics devices, hardware devices, electronics components, logical circuits, memories, software codes, firmware codes, among other examples, or any combination thereof. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, application, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, and/or functions, among other examples, whether referred to as software, firmware, middleware, microcode, hardware description language or otherwise. In addition, features discussed herein may be implemented via specialized processor circuitry, via executable instructions, or combinations thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure. Skilled artisans will also readily recognize that the order or combination of components, methods, or interactions that are described herein are merely examples and that the components, methods, or interactions of the various aspects of the present disclosure may be combined or performed in ways other than those illustrated and described herein.

The various illustrative logics, logical blocks, modules, circuits and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware or software depends upon the particular application and design constraints imposed on the overall system.

The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single-or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or, any conventional processor, controller, microcontroller, or state machine. In some implementations, a processor may be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular processes and methods may be performed by circuitry that is specific to a given function.

In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware, including the structures disclosed in this specification and their structural equivalents thereof, or in any combination thereof. Implementations of the subject matter described in this specification also may be implemented as one or more computer programs, that is one or more modules of computer program instructions, encoded on a computer storage media for execution by, or to control the operation of, data processing apparatus.

If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. The processes of a method or algorithm disclosed herein may be implemented in a processor-executable software module which may reside on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that may be enabled to transfer a computer program from one place to another. A storage media may be any available media that may be accessed by a computer. By way of example, and not limitation, such computer-readable media may include random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store desired program code in the form of instructions or data structures and that may be accessed by a computer. Also, any connection may be properly termed a computer-readable medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine readable medium and computer-readable medium, which may be incorporated into a computer program product.

Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to some other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

Additionally, a person having ordinary skill in the art will readily appreciate, the terms “upper” and “lower” are sometimes used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of any device as implemented.

Certain features that are described in this specification in the context of separate implementations also may be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also may be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted may be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products. Additionally, some other implementations are within the scope of the following claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve desirable results.

As used herein, including in the claims, the term “or,” when used in a list of two or more items, means that any one of the listed items may be employed by itself, or any combination of two or more of the listed items may be employed. For example, if a composition is described as containing components A, B, or C, the composition may contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination. Also, as used herein, including in the claims, “or” as used in a list of items prefaced by “at least one of” indicates a disjunctive list such that, for example, a list of “at least one of A, B, or C” means A or B or C or AB or AC or BC or ABC (that is A and B and C) or any of these in any combination thereof. The term “substantially” is defined as largely but not necessarily wholly what is specified (and includes what is specified; for example, substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. In any disclosed implementations, the term “substantially” may be substituted with “within [a percentage] of” what is specified, where the percentage includes 0.1, 1, 5, or 10 percent.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.